This application claims the priority of German application 100 26 448.4, filed May 27, 2000, the disclosure of which is expressly incorporated by reference herein.
This invention refers to a trochoidal design rotary piston engine with a rotary housing, two side disks with a bearing-mounted eccentric shaft and a bearing-mounted rotary piston on the eccentric shaft.
In such rotary piston engine, as it is also known, for example, from the German Patent Document No. DE-C 40 03 663 (corresponding U.S. Pat. No. 5,199,863), the side parts are usually made as cast construction parts. Aluminum alloys are a well-known material used in order to reduce the weight of the engine. In the particularly highly stressed rotary piston engines of this design, fissures have occurred after extended running time, especially when supercharging has been undertaken. This formation of cracks can lead to a loss of the engine. The fissuring can be avoided when the strength of the material is increased. Such increase in the strength of the material, however, leads to an increase in engine weight.
An object for this invention was the accomplishment of the task of finding the most cost effective material to make side disks for the above-described type rotary piston engine, which could be produced at low cost to provide a high level of strength at low weight.
This object has been achieved according to preferred embodiments of the invention in that the side disk is manufactured from a sealed cover disk and a load bearing composite side part made as a cast unit with an engine combustion compartment defining wall, an external bearing rim, and an internal bearing support where the wall and the far side of the engine combustion compartment are reinforced with ribs.
A very high strength at low weight can be achieved by splitting of the side disk according to this invention. The component contours of the cast bearing construction unit are visible only on the side that is open to the side (of the contours). That makes the side part simple to cast, for example, in an aluminum die cast unit process.
In a profitable production of this invention, at least two approximately radial direction tensile ribs are intended to be arranged at an angular distance of about 90 degrees. These tensile ribs are arranged at the beginning and end of the thermally and mechanically most stressed rotary piston housing and present a good transfer of power from the bearing support to the entire side section.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.